Phage

I can understand why some theories would say that time is infinite in the dimension of time, but what corroborates that? We already know that there was a start, and just because we have not come to an end does not mean that there will not be one. Sure, we cannot come up with a good reason for it to end (but then we don't really have a good reason for it to start anyway).

I take issue with your statement that nothing except mathematics in science is proven. For instance, anyone can go out and determine the boiling point of water at standard pressure. This is an observable phenomenon. Stating that the universe is infinite in size is not an observable phenomenon and cannot be proved correct, only disproved.

As you said, if theories are hard to disprove then your confidence in them becomes greater. However this only applies if it is reasonable that tests can be performed that would disprove the theory if it was wrong. An example of this in action: I propose that the center of the star Alpha Centauri A suddenly formed little green men last Tuesday. It is very difficult (impossible we presume) to disprove such a theory but it does not make any sense for us to gain confidence in it because of that.

Now look at the theory "Space is infinite in size." Is it within our capacity to disprove this theory? No, but it is also unreasonable to assume that it is within our capability at this time to disprove it were it false.

In any case, your point is well taken. Our discussion is based on current theories and views of the structure of the universe and are very likely to change as we progress. One day we may be looked back at in the same way we look back at those who believed that the world was flat.